Answer:
v = 158 m / s
Explanation:
In this kinematic problem they give us the acceleration of the body, the position and speed of the initial moment, let's use the definition of acceleration
a = dv / dt
dv = a dt
We integrate
∫ d v = ∫ (2t + 1) dt
v = 2 (2t²) + 1t
We evaluate between the initial time t = 0 that has speed (vo) 8 m/s and the final time t with speed v
v -8 = 4t2 + t
We already have the velocity formula as a function of time, let's calculate for t = 6 s
v = 8 + 4 6² +6
v = 158 m / s